Proactive readiness check before switchover to standby database

Hello experts,

                     I have below configuration of undo_tablespace parameter in primary db (pstp) and standby db(pstdr).

Primary db(pstp):-

SQL> select inst_id,name,value from gv$parameter where name='undo_tablespace';

   INST_ID NAME                           VALUE
---------- ------------------------------ --------------------
         1 undo_tablespace                UNDOTBS01
         4 undo_tablespace                UNDOTBS04
         3 undo_tablespace                UNDOTBS03
         2 undo_tablespace                UNDOTBS02

Standby db(pstdr):-

SQL> select inst_id,name,value from gv$parameter where name='undo_tablespace';

   INST_ID NAME                           VALUE
---------- ------------------------------ --------------------
         2 undo_tablespace                UNDOTBS2
         1 undo_tablespace                UNDOTBS1
         4 undo_tablespace                UNDOTBS4
         3 undo_tablespace                UNDOTBS3

From alert log I can see below but similar kind of operation not found in dr database.Now my question is